1. FIELD OF THE INVENTION
The present invention relates generally to a telephone terminal equipment in which telephone numbers of callers are displayed, and more particularly to a telephone terminal equipment in which telephone numbers relating to no-response are explicitly displayed.
2. DESCRIPTION OF THE RELATED ART
When a caller give a telephone call to a subscriber, a ring signal and a piece of telephone number data indicating a telephone number of the caller are conventionally sent together to the subscriber. The telephone number data of the caller is added to the ring signal at a telephone exchange as a service. Thereafter, the telephone number of the caller is displayed on a telephone set of the subscriber after the telephone number data is decoded to the telephone number of the caller. Therefore, the subscriber can identify the caller before the subscriber takes up a handset of the telephone unit to place a call.
Accordingly, an unnecessary telephone communication with the caller can be prevented to save the time because the subscriber can identify the caller without communicating with the caller.
Also, because the telephone number of the caller is displayed on the telephone set of the subscriber, usage of telephone communication for the wrong purpose can be reduced.
Previously Proposed Art
A conventional telephone unit is described with reference to FIG. 1.
FIG. 1 is a block diagram of a conventional telephone unit.
As shown in FIG. 1, a conventional telephone unit 11 at a subscriber's side is provided with a ring signal detecting circuit 12 for detecting a ring signal transferred from a telephone exchange (not shown) through telephone lines 13, a ringing tone generating circuit 14 for generating ringing tones when the ring signal is detected in the ring signal detecting circuit 12, a speaker 15 for outputting the ringing tones generated in the ringing tone generating circuit 14, a telephone number detecting circuit 16 for detecting a piece of telephone number data indicating a telephone number of a caller, a control circuit 17 including a microcomputer for decoding the telephone number data to the telephone number, a memory circuit 18 for storing the telephone number decoded in the control circuit 17 under control of the control circuit 17, a displaying circuit 19 including a liquid crystal display (LCD) for displaying the telephone number decoded in the control circuit 17 under control of the control circuit 17, and a handset 20 detachably attached on a hook switch 21.
In the above configuration, the conventional telephone unit 11 is usually in a waiting mode which corresponds to a on-hook condition in which the handset 20 is attached on the hook switch 21 to wait for a telephone call. When a caller dials to give a telephone call to the subscriber, a dial signal is transferred to the telephone exchange. Thereafter, the conventional telephone unit 11 at the subscriber's side is specified in the telephone exchange because the dial signal designates the unit 11. Therefore, a series of ring signals is generated in the telephone exchange, and a piece of telephone number data indicating the telephone number of the caller is added so as to follow a first ring signal of the ring signals in the telephone exchange. Thereafter, the ring signals and the telephone number data are transferred to the conventional telephone unit 11 through the telephone lines 13. Therefore, each of the ring signals is intermittently detected in the ring signal detecting circuit 12, and the telephone number data indicating the telephone number of the caller is detected in the telephone number detecting circuit 16.
When the first ring signal is detected in the ring signal detecting circuit 12, a detecting signal is transferred from the ring signal detecting circuit 12 to the control circuit 17. Also, the detecting signal is transferred to the ringing tone generating circuit 14 each time one of the ring signals is detected in the ring signal detecting circuit 12. Thereafter, a ringing tone is generated in the ringing tone generating circuit 14 each time the detecting signal is received in the ringing tone generating circuit 14. Therefore, ringing tones are intermittently output from the speaker 15.
When the telephone number data is detected in the telephone number detecting circuit 16, the telephone number data is transferred to the control circuit 17. In this case, because the detecting signal has been already received in the control circuit 17, the telephone number data is promptly decoded to a telephone number of the caller, and the telephone number is stored in the memory circuit 18 under the control of the control circuit 18. Also, the telephone number is promptly displayed on a liquid crystal display of the display circuit 19.
The conventional telephone unit 11 is additionally provided with an interface circuit 22 through which the handset 20 is connected with the telephone lines 13 under control of the control circuit 17, a receiving circuit 23 for transmitting an aural signal transferred from the caller to a receiver of the handset 20 through the telephone lines 13 and the interface circuit 22, a transmitting circuit 24 for transmitting another aural signal of the subscriber input in a microphone of the handset 20 to the caller through the interface circuit 22 and the telephone lines 13, and a displaying switch 25 operated by the subscriber to display all of telephone numbers stored in the memory circuit 18 on the liquid crystal display of the displaying circuit 19.
In the above configuration, in cases where the handset 20 is in the on-hook condition, the handset 20 is disconnected with the telephone lines 13 under control of the control circuit 17. In contrast, when the subscriber hears the ringing tones output from the speaker 15, the subscriber looks at the telephone number displayed on the liquid crystal display of the displaying circuit 19 and takes up the handset 20 attached on the hook switch 21 to talk with the caller. At this time, the hook switch 21 is switched on, and a switch-on signal is transferred from the hook switch 21 to the control circuit 17. Therefore, the handset 20 is set to an off-hook condition. That is, the interface circuit 22 is controlled by the control circuit 17 to connect the handset 20 to the telephone lines 13. Also, the generation of the ringing tones in the ringing tone generating circuit 14 is stopped under control of the control circuit 17. Therefore, the output of the ringing tones in the speaker 15 is stopped.
When the handset 20 is set to the off-hook condition, an aural signal indicating a voice of the caller is transferred to the receiving circuit 23 through the interface circuit 22 so that the voice of the caller is output from the receiver of the handset 20. Also, a voice of the subscriber received in the microphone of the handset 20 is converted into an aural signal of the subscriber in the transmitting circuit 24, and the sound signal of the subscriber is transferred to the caller through the interface circuit 22 and the telephone lines 13. Therefore, the subscriber can talk with the caller in a two-way conversation.
In addition, a plurality of telephone numbers of callers are automatically stored one by one in the memory circuit 18 in the order of telephone calls regardless of whether the handset 20 is set in the off-hook condition. Also, when the subscriber leaves his house, the subscriber can set the conventional telephone unit 11 from the waiting mode to an absent mode. Therefore, in cases where the conventional telephone unit 11 is in the absent mode, each of the telephone numbers is automatically stored in the memory circuit 18 with a reference code indicating the absent mode. In this case, when the subscriber returns home, the subscriber can identify the telephone numbers stored in the absent mode by pushing down the displaying switch 25. In other words, the subscriber can distinguish the telephone numbers stored in the absent mode from the telephone numbers stored in the waiting mode.
Problems to be Solved by the Invention
However, in cases where the subscriber often leaves his house, it is troublesome to set the conventional telephone unit 11 to the absent mode. Therefore, the subscriber does not set the unit 11 to the absent mode as a practical matter when the subscriber leaves his house. In this case, when the subscriber is absent, the subscriber makes no response to telephone calls of callers having first telephone numbers. Therefore, the first telephone numbers relating to no-response are automatically stored one by one in the memory circuit 18 in the waiting mode. In contrast, when the subscriber is in home, the subscriber makes a response to each of telephone calls of callers having second telephone numbers. Therefore, the second telephone numbers corresponding to responded telephone calls are automatically stored one by one in the memory circuit 18 in the waiting mode. As a result, the first telephone numbers relating to no-response and the second telephone numbers corresponding to responded telephone calls are mingled together.
Accordingly, because all of the telephone numbers stored in the memory circuit 18 are displayed in the same waiting mode, there is a first drawback that the subscriber cannot distinguish the first telephone numbers relating to no-response from the second telephone numbers corresponding to responded telephone calls. That is, even though the subscriber intends to give telephone calls to the callers having the first telephone numbers relating to no-response, the subscriber cannot select the first telephone numbers.
Also, there is a case that the conventional telephone unit 11 is additionally provided with a tape recorder which automatically record a voice of a caller in the absent mode. In this case, even though the caller gives a telephone call to the subscriber when the subscriber is absent, the subscriber can hear the voice of the caller with the tape recorder when the subscriber returns home.
However, the telephone number of the caller is stored in the memory circuit 19 regardless of whether the voice of the caller is recorded in the tape recorder. Accordingly, even though the conventional telephone unit 11 is set to the absent mode each time the subscriber leaves his house, there is a second drawback that the subscriber cannot distinguish telephone numbers of callers whose voices are recorded in the tape recorder from telephone numbers of callers whose voices are not recorded in the tape recorder.